The present invention generally relates to a link member drive belt and more specifically relates to a drive belt to be used with a variable speed drive.
Drive belts for use with a variable speed drive are known in the art and examples of such belts are shown in U.S. Pat. Nos. 1,424,768; 2,177,410: 1,691,871; 1,940,297; 3,431,724 and 4,340,378.
Certain of these variable speed drives are known as Reeves drives.
The drive belt is used to transfer power from a driving shaft to a driven shaft. The two shafts are mounted with their axes in parallel. A pulley is mounted on each shaft. Each pulley has two radially extending spaced apart flanges. The pair of flanges on a shaft flare away from one another so that the surface of each flange has an angle to a plane perpendicular to the axis of the shaft. The belt extends between these pair of flanges. The links of the belt are thick and the edge surfaces of the links operate as the drive surfaces frictionally engaging the flanges. For proper operation, the pair of driving flanges have to be kept in alignment with the pair of driven flanges. This alignment assures that the drive belt will travel in a straight line and that the sloping edge surfaces of the links will engage the flange surfaces in a flush manner.
In use the axes of the two drive shafts tend to shift relative to one another in an axial direction. This causes one pair of flanges to get out of alignment with the other pair of flanges. The result is that the drive surfaces of the links on the drive belt improperly engage the flanges. The result is damage to the links of the drive belt and to the flanges. The drive belt wears and breaks. Grooves are worn into the flanges. To prevent belt breakage and excessive damage to the flanges, it is necessary to stop the operation at an uneconomic time in order to replace or repair the belt. The result is expensive down time. In addition, the drive belts are expensive items.
The distance between the flanges of one of the pulleys is adjusted to affect the drive ratio. One of the limitations of prior art drive belts is that a limit on the radius of curvature of the belt limits the drive ratio obtainable.
Prior art belts tend to overheat, causing a risk of fire. Prior art belts also absorb grease, thereby losing friction and increasing the risk of fire from overheating.
Accordingly, it is an object of the present invention to provide a link member drive belt which can adjust to flange misalignment.
Another object of the invention is to provide such a belt which is not easily broken and which wears well.
A further object of the invention is to provide such a belt with a low radius of curvature so that the belt can adjust to a wide range of drive ratios.
Yet another object of the invention is to provide a belt which is resistant to degradation in strength or frictional performance.
Still a further object of the invention is to provide such a belt which is relatively inexpensive to manufacture and maintain.